DispatcherServlet.getHandlerAdapter(Object handler)
protected HandlerAdapter getHandlerAdapter(Object handler) throws ServletException {
if (this.handlerAdapters != null) {
for (HandlerAdapter adapter : this.handlerAdapters) {
if (adapter.supports(handler)) {
return adapter;
}
}
}
throw new ServletException("No adapter for handler [" + handler +
"]: The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler");
}
如果handlerAdapters不为null，遍历handlerAdapters，如果HandlerAdapter支持处理request，返回HandlerAdapter。handlerAdapters有三个元素，分别是HttpRequestHandlerAdapter，SimpleControllerHandleAdapter,
RequestMappingHandlerAdapter。
一、HttpRequestHandlerAdapter
public class HttpRequestHandlerAdapter implements HandlerAdapter {
@Override
public boolean supports(Object handler) {
return (handler instanceof HttpRequestHandler);
}
@Override
@Nullable
public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
((HttpRequestHandler) handler).handleRequest(request, response);
return null;
}
@Override
public long getLastModified(HttpServletRequest request, Object handler) {
if (handler instanceof LastModified) {
return ((LastModified) handler).getLastModified(request);
}
return -1L;
}
}
HttpRequestHandlerAdapter：适配使用通用DispatcherServlet的HttpRequestHandler接口。supports支持处理的handle类型是HttpRequestHandler。处理handle的方法handle()调用HttpRequestHandler.handleRequest,返回的ModelAndView是null。
二、SimpleControllerHandleAdapter
public class SimpleControllerHandlerAdapter implements HandlerAdapter {
@Override
public boolean supports(Object handler) {
return (handler instanceof Controller);
}
@Override
@Nullable
public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
return ((Controller) handler).handleRequest(request, response);
}
@Override
public long getLastModified(HttpServletRequest request, Object handler) {
if (handler instanceof LastModified) {
return ((LastModified) handler).getLastModified(request);
}
return -1L;
}
}
SimpleControllerHandlerAdapter：适配使用通用DispatcherServlet的Controller工作流接口。supports支持的handle类型是Controller接口。处理handle的handle()方法调用Controller.handleRequest.
三、RequestMappingHandlerAdapter
AbstractHandlerMethodAdapter.supports(Object handler)
public final boolean supports(Object handler) {
return (handler instanceof HandlerMethod && supportsInternal((HandlerMethod) handler));
}
supports支持的handle类型是HandlerMethod。
RequestMappingHandlerAdapter.supportsInternal(HandlerMethod handlerMethod)
protected boolean supportsInternal(HandlerMethod handlerMethod) {
return true;
}
AbstractHandlerMethodAdapter.handle(HttpServletRequest request, HttpServletResponse response, Object handler)
public final ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
return handleInternal(request, response, (HandlerMethod) handler);
}
RequestMappingHandlerAdapter.handleInternal(HttpServletRequest request,HttpServletResponse response, HandlerMethod handlerMethod)
protected ModelAndView handleInternal(HttpServletRequest request,
HttpServletResponse response, HandlerMethod handlerMethod) throws Exception {
ModelAndView mav;
checkRequest(request);
// Execute invokeHandlerMethod in synchronized block if required.
if (this.synchronizeOnSession) {
HttpSession session = request.getSession(false);
if (session != null) {
Object mutex = WebUtils.getSessionMutex(session);
synchronized (mutex) {
mav = invokeHandlerMethod(request, response, handlerMethod);
}
}
else {
// No HttpSession available -> no mutex necessary
mav = invokeHandlerMethod(request, response, handlerMethod);
}
}
else {
// No synchronization on session demanded at all...
mav = invokeHandlerMethod(request, response, handlerMethod);
}
if (!response.containsHeader(HEADER_CACHE_CONTROL)) {
if (getSessionAttributesHandler(handlerMethod).hasSessionAttributes()) {
applyCacheSeconds(response, this.cacheSecondsForSessionAttributeHandlers);
}
else {
prepareResponse(response);
}
}
return mav;
}
1、checkRequest检查是否支持request的请求方法，request是否需要session。
2、如果synchronizeOnSession为true，获取session后调用invokeHandlerMethod，否则调用invokeHandlerMethod。invokeHandlerMethod执行handle处理方法。
3、设置响应头
RequestMappingHandlerAdapter.invokeHandlerMethod(HttpServletRequest request,HttpServletResponse response, HandlerMethod handlerMethod)
protected ModelAndView invokeHandlerMethod(HttpServletRequest request,
HttpServletResponse response, HandlerMethod handlerMethod) throws Exception {
ServletWebRequest webRequest = new ServletWebRequest(request, response);
try {
WebDataBinderFactory binderFactory = getDataBinderFactory(handlerMethod);
ModelFactory modelFactory = getModelFactory(handlerMethod, binderFactory);
ServletInvocableHandlerMethod invocableMethod = createInvocableHandlerMethod(handlerMethod);
if (this.argumentResolvers != null) {
invocableMethod.setHandlerMethodArgumentResolvers(this.argumentResolvers);
}
if (this.returnValueHandlers != null) {
invocableMethod.setHandlerMethodReturnValueHandlers(this.returnValueHandlers);
}
invocableMethod.setDataBinderFactory(binderFactory);
invocableMethod.setParameterNameDiscoverer(this.parameterNameDiscoverer);
ModelAndViewContainer mavContainer = new ModelAndViewContainer();
mavContainer.addAllAttributes(RequestContextUtils.getInputFlashMap(request));
modelFactory.initModel(webRequest, mavContainer, invocableMethod);
mavContainer.setIgnoreDefaultModelOnRedirect(this.ignoreDefaultModelOnRedirect);
AsyncWebRequest asyncWebRequest = WebAsyncUtils.createAsyncWebRequest(request, response);
asyncWebRequest.setTimeout(this.asyncRequestTimeout);
WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);
asyncManager.setTaskExecutor(this.taskExecutor);
asyncManager.setAsyncWebRequest(asyncWebRequest);
asyncManager.registerCallableInterceptors(this.callableInterceptors);
asyncManager.registerDeferredResultInterceptors(this.deferredResultInterceptors);
if (asyncManager.hasConcurrentResult()) {
Object result = asyncManager.getConcurrentResult();
mavContainer = (ModelAndViewContainer) asyncManager.getConcurrentResultContext()[0];
asyncManager.clearConcurrentResult();
LogFormatUtils.traceDebug(logger, traceOn -> {
String formatted = LogFormatUtils.formatValue(result, !traceOn);
return "Resume with async result [" + formatted + "]";
});
invocableMethod = invocableMethod.wrapConcurrentResult(result);
}
invocableMethod.invokeAndHandle(webRequest, mavContainer);
if (asyncManager.isConcurrentHandlingStarted()) {
return null;
}
return getModelAndView(mavContainer, modelFactory, webRequest);
}
finally {
webRequest.requestCompleted();
}
}
1、创建ServletWebRequest
2、获取WebDataBinderFactory
3、获取ModelFactory
4、创建ServletInvocableHandlerMethod，并设置argumentResolvers，returnValueHandlers，WebDataBinderFactory，parameterNameDiscoverer等属性
5、创建ModelAndViewContainer并添加所有输入FlashMap的值，调用initModel
6、创建AsyncWebRequest并设置Timeout属性
7、创建WebAsyncManager并设置属性
8、判断WebAsyncManager是否有ConcurrentResult，如果有则获取ConcurrentResult
9、invokeAndHandle执行实际handle处理方法
10、获取ModelAndView并返回
RequestMappingHandlerAdapter.getDataBinderFactory(HandlerMethod handlerMethod)
private WebDataBinderFactory getDataBinderFactory(HandlerMethod handlerMethod) throws Exception {
Class<?> handlerType = handlerMethod.getBeanType(); //@Controller标注的class类型
Set<Method> methods = this.initBinderCache.get(handlerType);
if (methods == null) {
methods = MethodIntrospector.selectMethods(handlerType, INIT_BINDER_METHODS);
this.initBinderCache.put(handlerType, methods);
}
List<InvocableHandlerMethod> initBinderMethods = new ArrayList<>();
// Global methods first
this.initBinderAdviceCache.forEach((controllerAdviceBean, methodSet) -> {
if (controllerAdviceBean.isApplicableToBeanType(handlerType)) {
Object bean = controllerAdviceBean.resolveBean();
for (Method method : methodSet) {
initBinderMethods.add(createInitBinderMethod(bean, method));
}
}
});
for (Method method : methods) {
Object bean = handlerMethod.getBean();
initBinderMethods.add(createInitBinderMethod(bean, method));
}
return createDataBinderFactory(initBinderMethods);
}
1、获取@Controller标注的Class类型
2、通过第一步得到的bean类型查找@InitBinder注解的方法并设置到initBinderCache中。
3、遍历initBinderAdviceCache，如果ControllerAdviceBean需要处理bean，则将controllerAdviceBean要处理的bean和controllerAdviceBean的method封装成InvocableHandlerMethod后设置initBinderArgumentResolvers和webBindingInitializer加入initBinderMethods集合。
4、遍历第二步得到的method集合，将bean和method装成InvocableHandlerMethod后设置initBinderArgumentResolvers和webBindingInitializer加入initBinderMethods集合。
5、createDataBinderFactory创建WebDataBinderFactory。
RequestMappingHandlerAdapter.getModelFactory(HandlerMethod handlerMethod, WebDataBinderFactory binderFactory)
private ModelFactory getModelFactory(HandlerMethod handlerMethod, WebDataBinderFactory binderFactory) {
SessionAttributesHandler sessionAttrHandler = getSessionAttributesHandler(handlerMethod);
Class<?> handlerType = handlerMethod.getBeanType();
Set<Method> methods = this.modelAttributeCache.get(handlerType);
if (methods == null) {
methods = MethodIntrospector.selectMethods(handlerType, MODEL_ATTRIBUTE_METHODS);
this.modelAttributeCache.put(handlerType, methods);
}
List<InvocableHandlerMethod> attrMethods = new ArrayList<>();
// Global methods first
this.modelAttributeAdviceCache.forEach((controllerAdviceBean, methodSet) -> {
if (controllerAdviceBean.isApplicableToBeanType(handlerType)) {
Object bean = controllerAdviceBean.resolveBean();
for (Method method : methodSet) {
attrMethods.add(createModelAttributeMethod(binderFactory, bean, method));
}
}
});
for (Method method : methods) {
Object bean = handlerMethod.getBean();
attrMethods.add(createModelAttributeMethod(binderFactory, bean, method));
}
return new ModelFactory(attrMethods, binderFactory, sessionAttrHandler);
}
1、获取SessionAttributesHandler
2、获取@Controller标注的Class类型
3、通过第二步得到的bean类型查找@ModelAttribute注解的方法并设置到modelAttributeCache中。
4、遍历modelAttributeAdviceCache，如果ControllerAdviceBean需要处理bean，则将controllerAdviceBean要处理的bean和controllerAdviceBean的method封装成InvocableHandlerMethod后设置argumentResolvers和WebDataBinderFactory加入attrMethods集合。
5、遍历第三步得到的method集合，将bean和method装成InvocableHandlerMethod后设置argumentResolvers和WebDataBinderFactory加入attrMethods集合。
ModelFactory.initModel(NativeWebRequest request, ModelAndViewContainer container, HandlerMethod handlerMethod)
public void initModel(NativeWebRequest request, ModelAndViewContainer container, HandlerMethod handlerMethod)
throws Exception {
Map<String, ?> sessionAttributes = this.sessionAttributesHandler.retrieveAttributes(request);
container.mergeAttributes(sessionAttributes);
invokeModelAttributeMethods(request, container);
for (String name : findSessionAttributeArguments(handlerMethod)) {
if (!container.containsAttribute(name)) {
Object value = this.sessionAttributesHandler.retrieveAttribute(request, name);
if (value == null) {
throw new HttpSessionRequiredException("Expected session attribute '" + name + "'", name);
}
container.addAttribute(name, value);
}
}
}
1、ModelAndViewContainer合并sessionAttributesHandler属性值
2、invokeModelAttributeMethods调用ModelAttribute方法填充Model。
3、查找@SessionAttributes的方法参数并将值设置到ModelAndViewContainer
ModelFactory.invokeModelAttributeMethods(NativeWebRequest request, ModelAndViewContainer container)
private void invokeModelAttributeMethods(NativeWebRequest request, ModelAndViewContainer container)
throws Exception {
while (!this.modelMethods.isEmpty()) {
InvocableHandlerMethod modelMethod = getNextModelMethod(container).getHandlerMethod();
ModelAttribute ann = modelMethod.getMethodAnnotation(ModelAttribute.class);
Assert.state(ann != null, "No ModelAttribute annotation");
if (container.containsAttribute(ann.name())) {
if (!ann.binding()) {
container.setBindingDisabled(ann.name());
}
continue;
}
Object returnValue = modelMethod.invokeForRequest(request, container);
if (modelMethod.isVoid()) {
if (StringUtils.hasText(ann.value())) {
if (logger.isDebugEnabled()) {
logger.debug("Name in @ModelAttribute is ignored because method returns void: " +
modelMethod.getShortLogMessage());
}
}
continue;
}
String returnValueName = getNameForReturnValue(returnValue, modelMethod.getReturnType());
if (!ann.binding()) {
container.setBindingDisabled(returnValueName);
}
if (!container.containsAttribute(returnValueName)) {
container.addAttribute(returnValueName, returnValue);
}
}
}
1、从modelMethods集合中选取元素并获取InvocableHandlerMethod，获取@ModelAttribute属性，如果@ModelAttribute不需要绑定将@ModelAttribute的name添加到bindingDisabled集合。否则执行invokeForRequest
2、获取getNameForReturnValue返回值名称
3、将返回值名为key，返回值为value添加到ModelAndViewContainer中。
ServletInvocableHandlerMethod.invokeAndHandle(ServletWebRequest webRequest, ModelAndViewContainer mavContainer,Object... providedArgs)
public void invokeAndHandle(ServletWebRequest webRequest, ModelAndViewContainer mavContainer,
Object... providedArgs) throws Exception {
Object returnValue = invokeForRequest(webRequest, mavContainer, providedArgs);
setResponseStatus(webRequest);
if (returnValue == null) {
if (isRequestNotModified(webRequest) || getResponseStatus() != null || mavContainer.isRequestHandled()) {
disableContentCachingIfNecessary(webRequest);
mavContainer.setRequestHandled(true);
return;
}
}
else if (StringUtils.hasText(getResponseStatusReason())) {
mavContainer.setRequestHandled(true);
return;
}
mavContainer.setRequestHandled(false);
Assert.state(this.returnValueHandlers != null, "No return value handlers");
try {
this.returnValueHandlers.handleReturnValue(
returnValue, getReturnValueType(returnValue), mavContainer, webRequest);
}
catch (Exception ex) {
if (logger.isTraceEnabled()) {
logger.trace(formatErrorForReturnValue(returnValue), ex);
}
throw ex;
}
}
1、invokeForRequest执行实际handle处理方法
2、setResponseStatus设置响应状态
3、mavContainer设置requestHandled属性
4、处理返回值
InvocableHandlerMethod.invokeForRequest(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,Object... providedArgs)
public Object invokeForRequest(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,
Object... providedArgs) throws Exception {
Object[] args = getMethodArgumentValues(request, mavContainer, providedArgs);
if (logger.isTraceEnabled()) {
logger.trace("Arguments: " + Arrays.toString(args));
}
return doInvoke(args);
}
1、getMethodArgumentValues获取方法参数
2、调用doInvoke执行实际handle处理方法
InvocableHandlerMethod.getMethodArgumentValues(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,Object... providedArgs)
protected Object[] getMethodArgumentValues(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,
Object... providedArgs) throws Exception {
MethodParameter[] parameters = getMethodParameters();
if (ObjectUtils.isEmpty(parameters)) {
return EMPTY_ARGS;
}
Object[] args = new Object[parameters.length];
for (int i = 0; i < parameters.length; i++) {
MethodParameter parameter = parameters[i];
parameter.initParameterNameDiscovery(this.parameterNameDiscoverer);
args[i] = findProvidedArgument(parameter, providedArgs);
if (args[i] != null) {
continue;
}
if (!this.resolvers.supportsParameter(parameter)) {
throw new IllegalStateException(formatArgumentError(parameter, "No suitable resolver"));
}
try {
args[i] = this.resolvers.resolveArgument(parameter, mavContainer, request, this.dataBinderFactory);
}
catch (Exception ex) {
// Leave stack trace for later, exception may actually be resolved and handled...
if (logger.isDebugEnabled()) {
String exMsg = ex.getMessage();
if (exMsg != null && !exMsg.contains(parameter.getExecutable().toGenericString())) {
logger.debug(formatArgumentError(parameter, exMsg));
}
}
throw ex;
}
}
return args;
}
1、获取方法参数
2、遍历方法参数，findProvidedArgument解析providedArgs参数，如果存在则执行下一轮循环。否则执行resolvers.supportsParameter判断是否支持解析参数类型。不支持抛出异常。
3、解析参数
HandlerMethodArgumentResolverComposite.supportsParameter(MethodParameter parameter)
public boolean supportsParameter(MethodParameter parameter) {
return getArgumentResolver(parameter) != null;
}
HandlerMethodArgumentResolverComposite.getArgumentResolver(MethodParameter parameter)
private HandlerMethodArgumentResolver getArgumentResolver(MethodParameter parameter) {
HandlerMethodArgumentResolver result = this.argumentResolverCache.get(parameter);
if (result == null) {
for (HandlerMethodArgumentResolver resolver : this.argumentResolvers) {
if (resolver.supportsParameter(parameter)) {
result = resolver;
this.argumentResolverCache.put(parameter, result);
break;
}
}
}
return result;
}
遍历argumentResolvers，判断HandlerMethodArgumentResolver是否支持解析参数，如果支持解析参数则将参数为key，HandlerMethodArgumentResolver为value设置到argumentResolverCache。
HandlerMethodArgumentResolverComposite.resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory)
public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
HandlerMethodArgumentResolver resolver = getArgumentResolver(parameter);
if (resolver == null) {
throw new IllegalArgumentException("Unsupported parameter type [" +
parameter.getParameterType().getName() + "]. supportsParameter should be called first.");
}
return resolver.resolveArgument(parameter, mavContainer, webRequest, binderFactory);
}
1、获取参数解析器
2、解析参数
没有加注解的非简单类型由ModelAttributeMethodProcessor.resolveArgument解析参数。
HandlerMethodReturnValueHandlerComposite.handleReturnValue(@Nullable Object returnValue, MethodParameter returnType,ModelAndViewContainer mavContainer, NativeWebRequest webRequest)
public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType,
ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {
HandlerMethodReturnValueHandler handler = selectHandler(returnValue, returnType);
if (handler == null) {
throw new IllegalArgumentException("Unknown return value type: " + returnType.getParameterType().getName());
}
handler.handleReturnValue(returnValue, returnType, mavContainer, webRequest);
}
1、选择返回值处理器
2、调用处理器处理返回值
HandlerMethodReturnValueHandlerComposite.selectHandler(@Nullable Object value, MethodParameter returnType)
private HandlerMethodReturnValueHandler selectHandler(@Nullable Object value, MethodParameter returnType) {
boolean isAsyncValue = isAsyncReturnValue(value, returnType);
for (HandlerMethodReturnValueHandler handler : this.returnValueHandlers) {
if (isAsyncValue && !(handler instanceof AsyncHandlerMethodReturnValueHandler)) {
continue;
}
if (handler.supportsReturnType(returnType)) {
return handler;
}
}
return null;
}
遍历returnValueHandlers，判断HandlerMethodReturnValueHandler是否支持处理返回值类型，如果支持则返回。
标签：handle,handler,Object,request,mavContainer,源码,return,HandleAdapter,handlerMethod From： https://www.cnblogs.com/shigongp/p/16860923.html